Russia developed and tested its first atomic bomb in 1949 and in competition with the United States built up its arsenal during the Cold War.
Soviet nuclear forces expanded rapidly in the 1950s and 60s driven by huge investment in technology. In 1953 the USSR exploded its first hydrogen bomb and in the following decade developed ballistic missiles, as well as computers and guidance systems.
The Soviet arsenal reached a zenith in 1986. With the collapse of the USSR in 1989, former Soviet states handed missiles and bombs stored on their soil back to Moscow.